This third part of the series on the Written Word was covering how books and writing helped the spread of global religions during the first millennium AD. And also how the needs of the religions helped spread literacy & printing. It was split into 3 sections - covering Christianity, Islam and Buddhism. Common to all three is the way that once the words are written down it's easier for prospective converts to find out about the religion in question, so it's easier for it to spread. And also theologians can more easily debate & discuss the finer points of detail if those details are written down and the same for everyone.

Christian writings have been in the form of bound codices from early on. This format was partly used because of the desire to restrict what was canon in the scriptures - so if you had your bound copy of the Bible then you had the books that you were supposed to and no more or less.

In Islam the tradition is that the Prophet Mohammed was illiterate, and thus the teachings in the Koran were initially preserved orally and subsequently written down by scribes. Writing has a dual significance - in the temporal world it was used pre-Islam for contracts and other things where the details needed to be fixed, and this is why the Koran was written down. In the spiritual sense it is also a metaphor for how Allah fixes what is happening in creation.

And Buddhism helped to drive the invention of printing in China. The belief is that there is virtue in repetition - making repeated images of the Buddha will gain you merit, for instance. So writing down the teachings of Buddhism and printing multiple copies of them will not just provide people with their own copy of the text but is inherently a religious undertaking.

Incidentally, I'm always mildly surprised that radio shows like this work - you can't see anything obviously, but the experts & Bragg describe things and you can normally visualise them and understand the point of what's going on.